Fluid-pressure device.



G. WESTINGHOUSE.

FLUID PRESSURE DEVICE.

APPLICATION FILED SEPT. 2s, 1909.

Patented Aug. 20, 1912.

2 SHEBTS-SHBET 1,

INVENTOR ATTORNEY WITNESSES:

G. WESTINGHOUSE.

FLUID PRESSURE DEVICE.

APPLICATION FILED SEPT. 2s. 1909.

Patented Aug. 20, 1912.

2 SHEETS-SHEET 2.

wfg WQ@ /m/E/vro/e 12.7%

By--a ATTORNEY form a relativel GEORGE WESTINGHOUSE, OF PITTSBURGH,PENNSYLVANIA.

FLUID-PRESSURE DEVICE.

Specification of Letters Patent.

Patented Aug. 20, 1912.

Application tiled September 28, 1909. Serial No. 520,089.

To all whom it may concern:

Be it known that I, GEORGE WEs'rING- HOUSE, a citizen of the UnitedStates, and a resident of Pittsbur h, in the county of Allegheny andState o? Pennsylvania, have invented certain new and useful Improvementsin Fluid-Pressure Devices, of which the following is a specifica-tion.

My resent invention is shown as embodied in a fluid cushion deviceparticularly adapted for use as a spring, which may be used in anyrelation where two bodies are so associated that resilient movement isdesirable, and especiall where one or the other of the bodies is subjectto sudden movements, vibrations, or shocks which it is undesirable tohave transmitted to the other of said bodies. Certain features relatingto the packing and lubrication of the joint between the cylinder and themember sliding lengthwise of the same are ap licable in any similarrelations where high pressures are to be sustained.

It will be understood that though capable of use in other relations, theinvention has been devised for use primarily in connection wit-hautomobiles, and the general object in view has been to embody theprinciples of resilient support by means of an elastic fluid cushion,such as air or gasY in a practical, self-contained, gas-tight devicecapable of movement for compression and extension and adapted to serveas a spring,P but to combine therewith all of the desirable features ofa shock absorber, the entire device being adapted to meet the exactingconditions and to stand the rough usage uired in connection withautomobiles, de ivery wa ons, trucks, railway rolling stock, etc.

prefer to make the devices in the form of telescoping tubes with thesmaller or inner tube u permOSt. The tubes are hermeticall c osed at the,outer ends and the inner tu is provided at the inner end withperipheral packing adapted to form a fluid tight joint,-and isinternally contracted to constricted assage, so that the flow of quid toand o between the xed volume space in the upper cylinder and thevariable space in the lower cylinder, is more or less throttled. Thefluid within the cylinder consists of a compressible medium such as airor other gas 1n the upper portion, and an incompressible medium, such asoil, glycerin, etc.,rlling the vlower AIn the particular orm portion,preferably `to a level above the packing.

The throttling effect at the lower end of the plunger cylinder isrendered asymmetric by means of a check valve adapted to remain normallyopen on the compression ,movement of the spring, but to cut off adesired portion of the lpassage upon the extension movement. y locatinthe valve below the normal level of the liquid, all of the fluid whichpasses to and from the fixed volume space is subject to the as etricthrottling action of the valve. oreover, the valve is normall below thesurface of the liquid when the evice is at rest, so that the valveoperates initially in the incompressible port-ion of the fluid medium.The normal internal pressure of the fluid medium is preferab y high, butfor convenience in practical operation of an automobile, is preferablynot higher than can be supplied by an eicient tire pump of the ordinarycommercial type.

An important feature of my invention consists in the use of a pumpadapted to withdraw any sur lus oil which may find its Y way past thepacking of the sliding joint between the cylinders, and to force it backinto the interior. Such pump is preferably arranged so as to apply acertain degree of suction between the sliding surfaces of the twocylinders at a point above or on the low pressure side of the packing,and this may serve in certain cases to pump small quantities of air intothe c linder, as well as to collect escaping oil. is of a capacityadapted to produce any noticeable increase of the internal pressure fromthis cause, I may provide an adjustable relief valve adapted to rmitescape of small uantity of air w en the internal pressure exceeds thedesired value.

In the preferred form, I arrange an an-` ing or on its low pressureside, and form the n cases where the pump A edges of the groove so thatit will tend to collect from the walls of the outer linder and drain tothe pump intake any 0 which may find its way past the joint.

Y The pump is preferablylocated within the device, and is operatedentirely by the reciprocating movement of theA rts'when in use. 'ownherein, the end ofthethrottle alvestemisusedasthe pump piston, and itsreciprocation is caused' by the reciprocating movements of the checkvalve caused by the flow of fluid. The arrangement is such that the pumppiston normally closes the intake, so that when the device is not in usereverse leaks are prevented not only by the usual pump valves, but alsoby the pumirpiston.

The valve is loosely mounted on the stem, so as to permit a cert-ainamount of lost motion between it and the valve stem. This serves torender the valve more sensitive in its movements, and, moreover, permitsthe movement in either direction to acquire a certain momentum before itencounters the resistance of the valve stem. This resistance, of course,includes inertia ofthe stem, sliding friction, and work done in pumping.

The fluid pressure available on the valve for causing the requiredstroke of the pump may be enormously multiplied without destroying theasymmetric resistance function, by arranging a secondary constrictionapproximately midway of the path of travel of the valve. Byproportioning this constriction to the size of the Valve, so as topermit the latter to pass through in either direction with only a smallclearance, practically all of the compression and extension efforts onthe device when inoperation may be efficiently applied to force movementof the valve during its passage through the constriction.

Where a pump is used in accordance with my present invention, thehermetic sealing of the plunger by its packing need not be so perfect asin other cases, but as the device may be required to stand without usefor long periods, I have devised an additional expedient for maintainingan adequate body of oil in contact with the packing lat all times. Tothis end, I arrange a supplemental packing below the main packing,'

and the space between this supplemental packing and the main packing isconnected by ducts with a reservoir or trap adapted to contain a supplyof oil in a position where it will flow by gravity down into the spacebetween the main and supplemental packings. In this way, the mainpacking and expanding rings therefor are in effect submerged in oil,regardless of the normal level of the oil in the device. The oil isdashed into the reservoir whenever the device is used, and is there heldduring periods of non-use. The pressure on both sides of the lower,supplemental packing being ythe same, this packing need be only tightenough to prevent leak of oil by gravity.

A feature of my invention which is of special utility in connection withthe initial charging and adjustment of relative amounts ofincompressible liquid and of compressible air, is the arrangement of theorifice of the charging pipe or passage at a desired predetermined levelin the compression member: When this arrangement is used, the liquid maybe charged into the cylinder to a level somewhat greater than isdesirable in use. The compressed air may then be introduced through thesame or another orifice. When the pressure of the air has been adjustedto suit the load and the parts are in a state of rest, the oil may beblown out through the inlet orifice until escape of air indicates thatthe orifice has been uncovered and that the oil is at the proper level.

Having thus described the principal` features of my invention in suchmanner as to enable those skilled in the art to practise the same, Iwill now describe a specific, useful embodiment thereof in connectionwith the accompanying drawings, in which- Figure 1 is a vertical centralsection of the device on the line 1 1, Fig. 3; Fig. 2

is an enlarged detail of the operating parts shown in Fig. 1 with theasymmetric check valve closed and the pump piston in the retractedposition; Fig. 3 is an enlarged plan view.

The lower cylinder 1 is hermetically closed at ythe bottom by screw plug2 formed with a discharge passage 3 which is normally closed by a screwplug 4. This cylinder provides the variable space 5, which is adaptedtobe increased or decreased by up or down movements of the plungercylinder 6.Y The latter is provided at the upper end with a hermeticscrew closure 7. As shown in the drawings, the lower end is screwthreaded at 8 to a plunger head provided with constricted fluid passagesindicated by the double headed arrow 10.

Themain packing of the plunger comprises a seat 11 for a cup washer 12,which is clamped thereagainst by a ring 13 carried by a screw" member14, screw threaded to the central cylindrical wall l5. The free edge ofthe cup washer is preferably cut square and is continuously springpressed against the outer cylinders wall by steel sprin expanding rings16, 16. These rings are o? sufficient power to maintain the free edge ofthe cup washer 'continuously in erfect contact with the cylinder walls.n he annular space adjacentI the free edge ef; the cup Washer 12,including the space containing the expanding ring 16, is supplied withoil from the annular reservoir 17, 17, by duct`18, formed in thecasting, duct 19 passing through clamping ring 13, ducts 20, preferablyformed by ling the groove on the back inner ring 16, and duct 21 formedby a similar cut in the bottom of both rings 16. These ducts provide acontinuous supply of oil filling all the space adjacent the packing 12and escape is prevented by mean-'s 22 arranged of the -supplementalpacking 1d t t e 1n con ac below the main packing and with the walls ofthe cylinder by expanding ring 23; Escape of oil from the annularreservoir '17 is prevented by the wall 24, so that an abundant supply ofoil will remain in the reservoir, even in case the normal level of theoil is below the normal position of the packing, or in case the packingshould be lifted above the oil, as might happen in case a large part ofthe normal load was removed from the device.

The means for applying suction to the sliding contact surfaces in therear of the main packing is arranged in the plunger head. This meansconsists of a pump having an intake 25 extending into operative'relation with the inner wall of cylinder 1. The intake is preferablysupplied through an annular recess or chamber 26 formed or provided withthin edges 26 and 26", adapted to clear the Contactin walls of thecylinders of surplus oil. T ese clearingcdges may be rigid, or ofresilient `or yielding material. The intake is provided with a checkvalve 27 of any known or desired construction and from this valve thepassage 28 leads to the pump cavity 29, whence the oil is dischargedthrough the outlet valve 30 and passage 31 leading to the interior ofthe device. I

The solid head 32 of the pump piston is arranged so as to cover theinlet passage 28 when the plunger is at the end of the expellingstroke'. By-this arrangement, leak of the pump during periods of non-useis prevented by the plunger 32, as well as by check valves 30 and 27.The pump is operated automatically by relative movement of the partswhen in use, and preferably by flow of the fluid medium to and frobetween cylinders 1 and 6. In the arrangement shown, the valve 40 isadapted to lift from its seat 41 and permit relative free fiow of thefluid medium on the compression stroke and on the return or extensionstroke to seat itself, thereby closing passage 42 and forcing the tiuidto pass through the relatively smaller passages 43, 43. The effectivetotal area of the passages 43 and the relation of such area to theareaof the passage 42, will determine the extent to which the How to thevariable space 5 on the extension stroke will be conthis lost motionmounting, permits' the valve to move `freely into'clos'e' proximity to asecondary constriction 47, which conforms closely to the diameter ofthevalve, so that there is small clearance and practically the entirecompression and extension efforts are available to drive the valve, andthrough it the pump piston at the moment when the valve passes throughsaid constriction at 47. The upward or discharge movement of the pump ispreferably caused or assisted by a tension spring 50, ^secured to thecollar 44 and to the outside of the plunger bearing.

.I prefer to arrange an exterior or guard cylinder 51 screwed to theclosure of the cylinder 6 and engaging the outside of cylinder 1, at thethickened annular ed e 52 and at the lower packing 53. The thic enedannular edge 52 is preferably provided with a cushion or packing 54adapted to perform the function of a buffer whenever the com pressionstroke is sufficiently violent to drive the tiange of closure 7 downinto con-- tact therewith. The annular space 56 above packing 54 may beutilized as air compression space, in which air compressed by themovements of 52 may be utilized to maintain an initial pressure greaterthan atmosphere Within the annular space 26.

The arrangements for charging the device with oil and compressed air arepreferably located in head 7 of cylinder 6. As shown in Fig. 1, an inlettube 60 extends down a desired distance, so that its outlet orifice 61is at or about the desired level of the liquid to be used. The passageof air or liquid through this tube is controlled by a needle valveindicated at 62. As indicated in Fig. 3, there is a passage 64 leadingfrom the needle valve chamber to an inlet check valve 65, whichcommunicates with a screw threaded opening 66, to which may be connectedsupply pipes for oil or compressed air. In charging the device oil maybe introduced either by removing needle valve 62 and substituting an oilsupply pipe, or needle valve 62 may be merely loosened and the oilsupplied through the opening 66 and check valve 65. After oil has beencharged into the device to a suitable height, which is preferably abovethe level of the orifice 61 of pipe 60, the compressed air is introducedthrough 66, 65, 64, 60, until the in ternal pressure is sufficient tosupport the desired load with the parts approximately in the positionindicated in Fig. 1. e air supply is then detached and surplus oil blownout through pipe 60, until the escape of air indicates that its orificehas been uncovered by the lowering of the level of the luuid. If it isfound that the device has co lapsed an ap reciable amount owing to thelowering o the oil level as just described, enou h air may be addedtobring the parts to t e positipp indicated inIFig. 1.

The plug valve 62 and the plug 67 are then screwed tight and the deviceis in condition for use.

Where the pumping capacity of the pump described above is suflicient` toraise the internal pressure of the device, undue raise of pressure maybe prevented by an automatic relief valve, which is diagrammaticallyindicated in Fig. 3 as comprising a plug valve 70, closing spring 71,and screw adjusting means 72 for adjusting the initial pressure of thespring to thereby predetermine the maximum internal pressure, which maybe maintained in the device.

The annular collecting groove or chamber 26 is preferably ofconsiderably greater liquid capacity than would be necessary whenl thedevice is in continuous use and the pump in more or less continuousoperation.

With a groove of the size shown, the device may stand for long periodsunder very heavy loads and considerable oil may leak through the mainpacking without the possibility of any oil passing above said collectinggroove, which forms a break in the capillary path between the closefitting surfaces of the two cylinders, which break can only be bridgedby complete filling of the collecting space. It will thus be evidentthat up to the capacity of the latter space, the device is `proofagainst ultimate loss of oil or internal pressure, because all oilcontained in such space will be returned to the interior of the cylinderby the pump as soon as the latter is put in action by thereciprocating'movements of the parts, attendant upon normal active usethereof.

The reserv-oir oil space 17 is out of the direct path of to and fromovement of fluid, and, hence, the main body of the oil Inay be churnedinto foam to a considerable depth while a body of relativelylindisturbed oil will remainKto cover the ducts 18. Moreover, any foamabove the level of 24 will constitute a source of replenishment forreservoir 17 by reason of the oil which` will settle out of the foam andflow down into said reservoir.

The liquid used is preferably pure, free flowing, mineral oil, and itmay be mixed with pure, perfectly pulverized graphite.

The above described device ispprovided at both ends with journals 80,S0, adapted to engage pivots of a universal joint comprising pivotsarranged at right angles to each other anda coperating bracket attachedto one of the members to be cushioned by said device. l Y

Various features of my invention are adapted for use in other relationswhere the conditions and .functions to be served are similar, as, forinstance, in other devices wherein .a sliding joint is requiredtosustain great pressures without leaking; also they may be used as asupplement to or subscribed, and have pointed out in the ap' pendedclaims certain novel features of construction, arrangement, andoperation which characterize my invention, it will be understood bythose skilled in the art that various omissions, substitutions, andchanges in the forms, proportions, sizes, and details of the device andof its operation, may/be made without departing from my invention.

I claim:

1. The combination with members having a sliding joint therebetween andforming a chambered device' capable of movement for compression andextension, of liquid and gaseous fluids within the chamber, and a pumpwithin, said chamber for transferring liquid from said joint to saidchamber. l

2. The combination with ,members having a sliding joint therebetween andforming a chambered device capable of movement for compression andextension, of packing for said sliding joint, liquid and gaseous fluidswithin the chamber and a pump within said chamber for transferringliquid from the rear or low pressure side of said packing to saidchamber.

3. The combination with members having a sliding joint therebetween andforming a chambered device capable of movement for compression andextension, of packing for said sliding joint, liquid and gaseous fluidswithin the chamber, and a pump the operation of which is dependent uponthe compression and extension movements, `for transferring liquid fromthe rear or low pressure'side of said packing to said chamber.

4. Thecombination with members having a sliding joint therebetween andforming a chambered device capable of movement for compression andextension, of packing for said sliding joint, a constriction Within saidchamber substantially midway between its ends when extended, a umpwithin said chamber, the inlet of wh1ch is in operative connectionwith`said sliding joint and the discharge of which connects with saidchamber, and means reciprocable through said constriction for operatingsaid pump.

5. A cushion device comprising relatively movable ,members forming: achamber and having a sliding joint therebetween to permit variation ofthe volumetric capacity thereof; liquid and gaseous fluids within saiddevice,fand a fluid flow actuated pump located ywithin said devicey@having an inlet connection with the sliding joint, andan outletconnection to the interior of the' dev1ce.

6. A cushion device comprising relatively movable members forminga'chamber and having a sliding joint therebetween to permit variation ofthe volume of the fluid contained therein; liquid and gaseous fluidswithin said chamber, and a pump located within said chamber and'actuatedby fluid ow therein to pump fluid into said chamber.

7. A cushion device comprising relatively movable members forming achamber and having a sliding joint therebetween to per- Y mit variationof the volume of the fluid contained therein, liquid and gaseous fluidswithin said chamber and means for forcibly withdrawing the escapingfluid from the low pressure side of the sliding joint and returning itto the high pressure side.

8.v A cushion device comprising a cylinder, a plunger fitted to slidewithin said cylinder to permit variation of the volumetric capacitythereof, a main packing for the Sliding joint between said plunger andcylinder, and a supplemental packing below and adjacent said mainpacking on its high pressure side, closing in Van oilspace between themain and supplemental packings, in combination with a collecting cavityfor oily on the rear or low pressure side of the main packing and meansfor applying suction to said collecting cavity.

9. A cushion device comprisinga cylinder, a plunger fitted to slidetherein to permit variation of the volumetric capacity there? of, amainpacking for the sliding joint be-v tween said plunger and cylinder, asupplemental paclnng below and adjacent the main packing on itshighpressure side for retain-- ing oil in contact with said main packing,and means for lilling the space between said main and supplementalpackings with oil at a pressure substantially equal to the pressurewithin said cylinder.

10. A cushion device comprising a lcylinder, a plunger litted to slidetherein to permit variation of its volumetric capacity, a main packingfor the sliding joint between said plunger and cylinder, a supplementalpacking adjacent the main packing on its high pressure side forming aspace for retaining oil in contact with the high pressure side of themain packing, and means for filling said space with oil ata pressuresubstantially equal to the pressure within the cylinder, in combinationwith means for applying suction to the sliding joint on the lowpressureside of the main packing.

11. A cushion device comprising a cylinder, a plunger fitted to slidetherein to permit .variation of the `volumetric capacity thereof, a mainpacking for the sliding joint between said lunger and cylinder, asupjplemental pac (ing below and adjacent the main packing on its highpressureside for retaining oil in contact with said main packing, and areservoir above said main packing for supplying the space between saidmain and supplemental packings with oil at a pressure substantiallyequal to the pressure within said cylinder.

12. A cushion device comprisinga cylinder, a plunger fitted to slidetherein to permit variation of its volumetric capacity, a main packingfor the sliding joint between said plunger and cylinder, a supplementalpacking adjacent the main packing on its high pressure side forming aspace for retaining oil in contact with the high pressure side o themain packing, means for supplying said space with oil at a pressuresubstantially equal to the pressureywithin the cylinder, a collectingchamber on the low pressure side of the main packing, and means lforapplying suction to said collecting chamber.

13. A cushion device comprising relatively movable members forming aclosed chamber and having a sliding joint to per-Y mit variation of thevolume of the fluid contained therein, liquid and gaseous fluids withinsaid chamber arranged so that a body of the liquid fluid is maintainedin contact with the slidingjoint on its high pressure side, and meanswithin said chamber for applying suction to the rear portion or lowpressure side' of said sliding joint.

14. A cushion device comprising relatively movable members forming aclosed chamber having a sliding joint to permit varying the volume ofthe fluid contained therein, liquid and gaseous fluids within saidchamber arranged so that a body of liquid is maintained in contact withthe high pressure side of the slidin joint, and a pump having intakeconnection with the sliding joint and an outlet connection with saidchamber.

15. A cushion device comprising relatively movable members formiiig aclosed chamber, having a sliding joint to permit varying the volume [ofthe fluid contained therein, an agent for applying suction to the rearportion of the sliding joint, and means for utilizing the relativemovement of said members for o erating said agent.

16. A cushi n device comprising a cylinder, a member having slidingengagement with said cylinder to permit variation of the volumetriccapacity thereof, a packing for the sliding joint `between said memberand cylinder, and means within said cylinder for applying suctidn to thesliding joint on the rear or low pressure side of said packing.

17. A cushion device comprising a cylinder, a member having slidingengagement Awith said cylinder to permit variation of the volumetriccapacity thereof, a pacln'ng for the sliding joint between said memberand cylinder, and means within said cylinder for removing material fromthe sliding joint and Vforcing it into said cylinder.V

18,. A cushion device comprising telescopically arranged cylinders, apacking for the sliding joint between said cylinders, a conthe slidingjoint between said member and cylinder,. .a 'constricted passage forflow of the iuid within the device, a check valve arranged to beforcibly moved by fluid flowing through said passage upon relativemovement of said cylinder and member, and aV lpump operated by saidcheck valve, h aving an intake on the rear or low pressure side of saidpacking and an outlet communicating with the interior of said cylinder.

20. A cushion device comprising in combination, telescopically arrangedcylinders, a.

plunger device carried by one of 'said cylinders, a packing for thesliding joint between said cylinders carried by said plunger device, anda pump adapted to be operated by the flow of fiuid through said plungerdevice to apply suction to said sliding joint on the low pressure sideof said packing. I

21. A cushion device comprising in combination, two cylindersconcentrically arranged and secured to a head member, a cylinderprovided with one closed end and arranged to slidebetween said twocylinders, a Apacking for the sliding joint between the inner of saidtwo cylinders, and a' pump within the chamber formed by said two innercylinders for applying suction to said sliding joint on the rear or lowVpressure side of said packing.

22. A cushion device comprising rela-l tively movable members forming achamber and having a sliding joint therebetween to permit varlation ofthe volumetric capacity thereof, liquid and gaseous fluids' within saidchamber arranged so that the only fluid which can escape through saidjoint would be essentially liquid, and means for forcibly returning theescaped fluid into said chamber.

23. A cushion device comprising relatively movable members forming achamber and having a sliding joint therebetween to permit varlation ofthe volumetric capacity thereof, liquid and gaseous fluids within saidchamber arranged so that the only Huid which can escape through saidjoint will be essentially liquid, and means for automatically returningthe escaped fluid intol said chamber. A

Signed at New York city, in the county of New York and State of NewYork, this27th day of September, A. D. 1909.

|lVitnessesi WM. H. CAPEL, 'H. C. TENER'.

GEO. wEsTINGHoUsE.

